Laser diodes in photon number squeezed state

The behavior of the mean photon number, photon number variance and field squeezing is investigated for the two two-level atoms prepared in a multiatom squeezed state coupled to the vacuum or thermal field. The value of superposition angle (θ) of the atomic states is found to affect the photon number variance as well as field squeezing. The bound on the sun-Poissonian field concerning the value of θ and input mean photon number is determined. One of the field quadrature is found to exhibit permanent squeezing for the vacuum input in a small range of the value of θ. It is shown that the input thermal photons degrade the sub-Poissonian character and spontaneous squeezing. However, a considerable amount of squeezing is obtained even in the presence of thermal photons.

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Photon-number variance in laser diodes with quiet pumps

Journal of the Optical Society of America B ◽

10.1364/josab.14.002193 ◽

1997 ◽

Vol 14 (9) ◽

pp. 2193 ◽

Cited By ~ 2

Author(s):

J. Arnaud

Keyword(s):

Laser Diodes ◽

Photon Number

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QUANTUM STATE CONTROL IN SEMICONDUCTOR p-n JUNCTIONS (I) — SQUEEZED STATE GENERATION IN SEMICONDUCTOR LASERS

International Journal of Modern Physics B ◽

10.1142/s021797929300250x ◽

1993 ◽

Vol 07 (08) ◽

pp. 1577-1652 ◽

Cited By ~ 2

Author(s):

Y. YAMAMOTO ◽

S. INOUE ◽

W. RICHARDSON ◽

S. MACHIDA

Keyword(s):

Coherent State ◽

Semiconductor Laser ◽

Semiconductor Lasers ◽

Shot Noise ◽

Photon Number ◽

Planck Equation ◽

Quantum Limit ◽

Squeezed State ◽

Standard Quantum Limit ◽

State Generation

Quantum statistical properties of laser light have been extensively studied for the last thirty years by using an operator Langevin equation, a density operator master equation, and a quantum mechanical Fokker-Planck equation. It has been generally accepted among physicists and quantum electronics engineers that an ideal laser operating at far above the threshold generates a coherent state of light. Various experimental facts such as the Poissonian photoelectron statistics, the shot noise limited photocurrent fluctuations, and the Gaussian distributions of optical homodyne detector output seem to support this. However, recent careful studies on a semiconductor laser have revealed that a semiconductor laser does not necessarily produce a coherent state of light, but generates a number-phase squeezed state, in which the photon-number noise is smaller than the standard quantum limit (shot noise limit or Poisson limit). This paper reviews the theoretical and experimental aspects of number-phase squeezed state generation by a semiconductor laser.

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STUDY ON QUANTUM CORRELATIONS FOR CIRCUIT QED STATES

International Journal of Modern Physics B ◽

10.1142/s0217979213500562 ◽

2013 ◽

Vol 27 (13) ◽

pp. 1350056 ◽

Cited By ~ 1

Author(s):

Y. H. JI ◽

Y. M. LIU

Keyword(s):

Quantum Discord ◽

Relative Phase ◽

Photon Number ◽

Quantum Correlations ◽

Superconducting Qubits ◽

Squeezed State ◽

Cavity Field ◽

Circuit Qed ◽

Study Results ◽

Average Photon Number

We investigate the dynamic evolution behaviors of entanglement and geometric quantum discord of coupled superconducting qubits in circuit QED system. We carefully analyze the effect of cavity field quantum state on the quantum entanglement and quantum correlations dynamic behaviors of coupling superconducting qubits. The results show that when the cavity field is in coherent state, with the average photon number increasing, the quantum discord death (including entanglement death) would become more difficult to appear, that is to say prolonging the survival time of quantum correlations will be a benefit for keeping the quantum correlations. When the cavity field is in squeezed state, the squeezed amplitude parameters are all too big or too small to keep the system quantum correlations. However, the further study results show that with the initial relative phase of coupling superconducting increasing, qubits can also keep the quantum correlations.

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SECOND-ORDER AND AMPLITUDE-SQUARED SQUEEZING OF THE TWO TWO-LEVEL ATOMS WITH SUPERPOSITION STATE PREPARATION

International Journal of Modern Physics B ◽

10.1142/s0217979293003747 ◽

1993 ◽

Vol 07 (26) ◽

pp. 4439-4450 ◽

Cited By ~ 3

Author(s):

MUBEEN A. MIR

Keyword(s):

Photon Number ◽

Vacuum State ◽

Second Order ◽

Squeezed State ◽

Superposition State ◽

Initial Field ◽

Squeezed Vacuum State ◽

Coherent Field ◽

Number Formula ◽

Average Photon Number

An analysis of the second-order and amplitude-squared (AS) squeezing is presented for the two atoms prepared in a two-atom squeezed state using coherent and squeezed field inputs. The system produce strong sqeezing and superposition angle (θ) is more effective for small values of average photon number [Formula: see text] as compared to that of large one. The degree of squeezing of both types increases as θ increases for coherent field input with small [Formula: see text]. Some values of θ for the initial field in a squeezed-vacuum state with any value of input squeezing can make one of the quadrature of the both types of squeezing permanently squeezed for T≥0. For the initial field in a more general squeezed state, the second-order and AS squeezing behave randomly for different values of θ.

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